Validation of an automated immunoglobulin G-only cytomegalovirus (CMV) antibody screening assay and an assessment of the risk of transfusion transmitted CMV from seronegative blood.
BACKGROUND
Cytomegalovirus (CMV) antibody donor screening assays have predominantly included both immunoglobulin G (IgG) and immunoglobulin M (IgM) detection. However, since in the majority of cases both CMV IgG and IgM are detected concomitantly during early seroconversion, CMV assays based only on IgG are now widely applied for donor screening.


METHODS
The performance of an automated microparticle CMV IgG assay (Abbott AxSYM CMV IgG microparticle enzyme immunoassay [MEIA]) was compared with an established total antibody blood screening assay (Abbott CMV Total AB EIA). Sensitivity and specificity were assessed using 5050 random blood donors and 13 seroconversion panels. A risk analysis was undertaken to estimate the residual risk of transfusion-transmitted CMV (TT-CMV) from presumptive seronegative blood components.


RESULTS
The EIA achieved marginally (but not significantly) better resolved sensitivity (100%) than the AxSYM IgG assay (99.93%). The AxSYM IgG resolved specificity (99.34%) was superior to the EIA (96.4%). This superiority was maintained (98.61%) when a modified cutoff was applied to the AxSYM IgG assay to achieve 100 percent resolved sensitivity. The seroconversion sensitivities of the EIA and the AxSYM IgG were equivalent, detecting the same bleed as positive in the majority of the seroconversion panels tested. The median TT-CMV residual risk estimate for the two assays was approximately 1 in 66,000 (range, 42,000-165,000).


CONCLUSIONS
The AxSYM IgG MEIA is suitable for blood donor screening and was optimized by applying a modified cutoff of 9 AU per mL. The modeling predicts that implementing the AxSYM IgG assay would not negatively impact the already very low risk of TT-CMV associated with seronegative blood components in Australia.
Seed
Clive R
CR
Australian Red Cross Blood Service, School of Surgery, University of Western Australia, Perth, Australia. cseed@arcbs.redcross.org.au
Piscitelli
Lisa M
LM
Maine
Gregory T
GT
Lazzarotto
Tiziana
T
Doherty
Kathleen
K
Stricker
Reto
R
Stricker
René
R
Iriarte
Beimar
B
Patel
Chandu
C
D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology*; D001782:Blood Donors; D003587:Cytomegalovirus / Q000276:immunology*; D003586:Cytomegalovirus Infections / Q000097:blood / Q000276:immunology* / Q000635:transmission*; D046148:Donor Selection / Q000379:methods*; D006801:Humans; D007124:Immunoenzyme Techniques / Q000295:instrumentation / Q000379:methods; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D007075:Immunoglobulin M / Q000097:blood / Q000276:immunology; D008954:Models, Biological; D012307:Risk Factors
D000914:Antibodies, Viral; D007074:Immunoglobulin G; D007075:Immunoglobulin M